XML 78 R56.htm IDEA: XBRL DOCUMENT v3.8.0.1
Debt - 2016 Loan and Security Agreement (Details) - USD ($)
3 Months Ended 12 Months Ended
Aug. 01, 2016
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Debt Instrument [Line Items]                        
Loss on extinguishment of debt   $ 0 $ 0 $ 0 $ 0 $ 0 $ 1,026,000 $ 0 $ 0 $ 0 $ 1,026,000 $ 0
Prepayment penalties on extinguishment of debt                   0 368,000 $ 0
Loan and Security Agreements 2014 and 2013                        
Debt Instrument [Line Items]                        
Loss on extinguishment of debt             1,000,000          
Prepayment penalties on extinguishment of debt             400,000          
Write-off of unamortized debt discounts             400,000          
Write-off of unamortized debt issuance costs             $ 200,000          
Revolving Credit Facility                        
Debt Instrument [Line Items]                        
Unrestricted cash required to be deposited with lenders   25,000,000               25,000,000    
Revolving Credit Facility | Line of Credit | Loan and Security Agreement 2016                        
Debt Instrument [Line Items]                        
Credit facility, maximum borrowing capacity $ 50,000,000.0                      
Credit agreement, amount outstanding $ 32,600,000 32,600,000               32,600,000    
Unused line of credit capacity, fee 0.25%                      
First and second anniversary fee for line of credit $ 31,250                      
Credit facility, remaining borrowing capacity   $ 17,400,000               $ 17,400,000    
Debt issuance costs           $ 200,000         $ 200,000  
Debt issuance costs, amortization period 3 years                      
Revolving Credit Facility | Line of Credit | Loan and Security Agreement 2016 | Prime Rate                        
Debt Instrument [Line Items]                        
Debt instrument, basis spread (as a percentage) 0.50%                      
Percentage increase in interest rate if adjusted EBITDA is negative at end of quarter 0.25%